<template>
  <canvas
    v-if="canvasId"
    class="ec-canvas"
    :id="canvasId"
    :canvasId="canvasId"
    @touchstart="touchStart"
    @touchmove="touchMove"
    @touchend="touchEnd"
    @error="error"
  >
  </canvas>
</template>

<script>
import WxCanvas from './wx-canvas'
import * as echarts from '../../subpackages/components/echarts.min.js'

function wrapTouch (e) {
  for (let i = 0; i < e.mp.touches.length; i += 1) {
    const touch = e.mp.touches[i]
    touch.offsetX = touch.x
    touch.offsetY = touch.y
  }
  return e
}

export default {
  props: {
    //   echarts: {
    //     required: true,
    //     type: Object,
    //     default() {
    //       return null;
    //     },
    //   },
    onInit: {
      type: Function,
      default: null
    },
    canvasId: {
      type: String,
      default: 'ec-canvas'
    },
    lazyLoad: {
      type: Boolean,
      default: false
    },
    disableTouch: {
      type: Boolean,
      default: false
    },
    throttleTouch: {
      type: Boolean,
      default: false
    }
  },
  onReady () {
    if (!echarts) {
      console.warn(
        '组件需绑定 echarts 变量，例：<ec-canvas id="mychart-dom-bar" ' +
          'canvas-id="mychart-bar" :echarts="echarts"></ec-canvas>'
      )
      return
    }

    if (!this.lazyLoad) this.init()
  },
  methods: {
    init (callback) {
      const version = wx.version.version.split('.').map(n => parseInt(n, 10))
      const isValid =
        version[0] > 1 ||
        (version[0] === 1 && version[1] > 9) ||
        (version[0] === 1 && version[1] === 9 && version[2] >= 91)
      if (!isValid) {
        console.error(
          '微信基础库版本过低，需大于等于 1.9.91。' +
            '参见：https://github.com/ecomfe/echarts-for-weixin' +
            '#%E5%BE%AE%E4%BF%A1%E7%89%88%E6%9C%AC%E8%A6%81%E6%B1%82'
        )
        return
      }

      const { canvasId } = this
      this.ctx = wx.createCanvasContext(canvasId,this);

      const canvas = new WxCanvas(this.ctx, canvasId)

      echarts.setCanvasCreator(() => canvas)

      const query = wx.createSelectorQuery().in(this);
      query
        .select(`#${canvasId}`)
        .boundingClientRect(res => {
          if (!res) {
            setTimeout(() => this.init(), 50)
            return
          }

          const { width, height } = res

          if (typeof callback === 'function') {
            this.chart = callback(canvas, width, height)
          } else if (typeof this.onInit === 'function') {
            this.chart = this.onInit(canvas, width, height)
          }

          if (!this.chart) {
            return
          }

          const { handler } = this.chart.getZr()

          this.handler = handler
          this.processGesture = handler.proxy.processGesture || (() => {})
        })
        .exec()
    },
    canvasToTempFilePath (opt) {
      const { canvasId } = this
      this.ctx.draw(true, () => {
        wx.canvasToTempFilePath({
          canvasId,
          ...opt
        })
      })
    },
    touchStart (e) {
      const { disableTouch, chart } = this
      if (disableTouch || !chart || !e.mp.touches.length) return
      const touch = e.mp.touches[0]
      this.handler.dispatch('mousedown', {
        zrX: touch.x,
        zrY: touch.y
      })
      this.handler.dispatch('mousemove', {
        zrX: touch.x,
        zrY: touch.y
      })
      this.processGesture(wrapTouch(e), 'start')
    },
    touchMove (e) {
      const { disableTouch, throttleTouch, chart, lastMoveTime } = this
      if (disableTouch || !chart || !e.mp.touches.length) return

      if (throttleTouch) {
        const currMoveTime = Date.now()
        if (currMoveTime - lastMoveTime < 240) return
        this.lastMoveTime = currMoveTime
      }

      const touch = e.mp.touches[0]
      this.handler.dispatch('mousemove', {
        zrX: touch.x,
        zrY: touch.y
      })
      this.processGesture(wrapTouch(e), 'change')
    },
    touchEnd (e) {
      const { disableTouch, chart } = this
      if (disableTouch || !chart) return
      const touch = e.mp.changedTouches ? e.mp.changedTouches[0] : {}
      this.handler.dispatch('mouseup', {
        zrX: touch.x,
        zrY: touch.y
      })
      this.handler.dispatch('click', {
        zrX: touch.x,
        zrY: touch.y
      })
      this.processGesture(wrapTouch(e), 'end')
    }
  }
}
</script>

<style scoped>
.ec-canvas {
  width: 100%;
  height: 100%;
}
</style>
